PIK-20 E Service manual
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Note 5 The toothed drive belt
When properly installed and when clean, the belt requires little
maintenance.
If the edges are worn it can be due to misalignment. Check
also the drive gear flange for straightness.
When the belt is in right tension, a 60 N force applied at the
midpoint of the span between the two pulleys should bend the
belt 2.5 mm (14 lbs, 3/32 in).
Excessive belt tension may cause excessive wear between
belt teeth. A too loose belt may lead to jumping of teeth and
cause vibrations.
Normally improper tension is a mark of some other defect
(improper gear center to center distance).
Changing the toothed drive belt
When the belt has worn too much, it should be changed.
Remove the propeller and the flange at the small belt drive
gear. Check that the position markings are aligned on the gears
to ensure the right installation of the new belt. Remove the belt
by pulling the belt and simultaneously turning the engine. Ins
tall a new belt in reverse order. Check the alignement of the
gear position markings.
If the belt feels very tight to install, check the right gear cen
ter to center distance.
■to
>o .
( 165.6 -0.3 mm; 6.520
0.012
In )
Note 6 Cylinder head bolts tightness
Cylinder head should be tightened to 20 Nm (180 in pounds)in
the first 25 hour maintenance. Dismount cooling baffles and
the lower engine supporting plate.
Note 7 Decompression valves
The decompression valves must be completely tight. Crank the
engine by hand and check the tightness. With closed valves
the gap between the rocker axle and valve head should be 3
mm (0.1 in). The spring on the cable must return the operating
lever fully. If not, lubricate the cable and check spring tension.
EIRI KY -
Kisällinkatu 8
SF 15170 Lahti 17
page 11-19